To achieve CDC (Colorless, Directionless and Contentionless)—ROADM (Reconfigurable Optical Add/Drop Multiplexer), multicast switches in which optical splitters and optical switches are combined together have been in use. As a multicast switch, a dual type multicast switch that is equipped with add/drop functions in one housing, such as 8×8 multicast switch, has been mainly used. In future, further increase in the number of wavelength is expected.
As one of the methods to reduce the size of the multicast switch, for example, a use of intersecting splitters in which waveguides are intersecting with each other on a same plane have been proposed, for example by International Patent Publication No. 2014/171083 (WO2014/171083).